Leaded gasolines



Research and Engineering Company, a corporation of 7 Delaware NoDrawing. Filed Aug. 5, 1957, Ser. No. 676,373 9 Claims. (Cl. 44-69) Thepresent invention relates to fuels for use in sparkignition internalcombustion engines and more particularly relates to improved additiveagents for use with tetraalkyl lead compounds which are adapted toreduce octane requirement increase, surface ignition and spark plugfouling in modern high compression gasoline engines and to leadedgasolines containing such improved additive agents. a

The problems associated with the use of volatile organic lead compoundssuch as tetrarnethyl lead and tetraethyl lead as anti-knock agents ingasolines are generally well recognized in the art. it is known thatsuch lead compounds, although they reduce engine knock attributable tocompression-ignition of the fuel-lair mixture and hence are valuablegasoline constituents, are detrimental in that they give rise to theformation of engine deposits which result in an increase in the fueloctane level required for satisfactory engine operation, commonlycalledQRl. or octane requirement increase; become incandescent andignite the fuel-air mixture prematurely by a phenomenon commonly calledsurface-ignition; and foul the points and insulators of spark plugs,thus causing rnisfire of the spark. In order to minimize the formationof such deposits and avoid these difliculties, it has always beencustomary to employ a scavenger agent, usually an alkyl halide such asethylene dichloride or ethylene dibromide, in approximately equimolarproportion with the lead compounds in leaded gasolines. Such scavengeragents are intended to provide halogen acids to combine with the leadafter combustion has begun and to sweep it as a relatively volatile leadhalide from the combustion cham- I ber,-but in practice it is found thatthe scavenger agents e only partially eiiective. Deposit formation andthe attendant difficulties occur despite their use,'particularly inmodern engines with very high compression ratios, i.e. above 9:1.

A number of different additive agents have been proposed heretofore forinclusion in leaded gasolines in order to overcome these difficulties.Several of these have proved reasonably effective in some respects, butit has been found that their use is generally accompanied bydisadvantages in other respects, such as a depression of the octanequality of the gasoline in which they are incorporated. Due to the highoctane requirement of modern automotive engines, i.e. the high octanenumber that the gasoline must have to give knock-free operation of theengines, and the practical limitations imposed upon the levels of octanenumber attainable in gasoline by available petroleum refining processes,the octane depressing or pro-knock properties of gasoline additives arebecoming increasingly important. The cost of raising gasoline octanenumber to overcome the depressing effect of such scavenging additives asare used in the gasoline may aired States Patent "ice amount to as muchas one cent per gallon at high octane levels and will increase to aneven higher figure as the octane requirements of engines continue torise. There is therefore a tremendous incentive to develop improvedgasoline scavenger additives free from octane depressing properties.

The additive agents of the present invention are effective for reducingoctane requirement increase, surface ignition and spark plug fouling andnot only do not depress the octane quality of the gasolines in whichthey are incorporated but in addition have numerous other advantagesover additive compositions which have been proposed heretofore. Thesenovel additive agents, which are particular mixtures of a monoalkyldiphenyl phosphote and a stoichiometric excess of a liquidhalohydrocarbon scavenger having a boiling point between 50 C. and 250C., preferably between C. and C., possess outstanding high temperaturestability properties, do not separate from the fuel at extremely lowtemperatures, decrease the tendency of gasoline to form gum uponoxidation, have very low water solubility and reactivity, and arecompatible with a wide variety of other additives commonly used ingasolines for various purposes.

The monoalkyl diphenyl phosphates used in the fuels of the inventionhave the general formula where R is an alkyl group containing from 6 toabout 10 carbon atoms. This chemical structure is critical for thepurpose of the present invention because it insures the proper degree ofchemical stability and physical solubility in gasoline without anylowering of octane number. Representative examples of such phosphatesinclude Z-ethylbutyl diphenyl phosphate'n-hexyl diphenyl phosphate, *2-ethylhexyl diphenyl phosphate, isooctyl diphenyl phosphate, n-octyldiphenyl phosphate and decyl diphenyl phosphate. The branched-chainmon-oalkyl diphenyl phosphates containing about 8 carbon atoms in thealkyl group are preferred for the reasons described above; and themonoalkyl diphenyl phosphate having an alkyl group containing 8 "carbonatoms and derived from a Cg'OXO alcohol, referred to as C -oxo diphenylphosphate, is particularly preferred for use in the fuels of theinvention.

The C -oxo alcohols are prepared by the ox'onation and subsequenthydrogenation of a Cr copolymer of propylene and butene. The copolymerconsists of a mixture of isomers, usually being derived from a refinerygas stream containing propylene and mixed normal and isobutylenes, andtherefore the Cg-DXO alcohol and the CgOXO diphenyl phosphate preparedfrom such alcohol consist of series of isomeric compounds. C -oxoalcohol normally has the following general analysis:

The C -oxo diphenyl phosphate prepared from C -oxo alcohol has alkylchains which correspond to those of the alcohol as set forth above andis thus a mixture of isomeric octyl diphenyl phosphates. Similarmixtures may be derived from mixtures oi primary alcohols containingfrom about 6 to about 10 carbon atoms per molecule and are suitable foruse in accordance with the invention. Other mixtures of monoalkyldiphenyl phosphates, having alkyl groups of from 6 to 10 carbon atoms,such as a mixture of 2 ethylhexyl diphenyl phosphate and decyl diphenylphosphate for example, may also be used.

The monoalkyl diphenyl phosphate esters may be readily synthesized byreacting POCI with an equivalent molar quantity of a suitable alcoholhaving 6 to 10 carbon atoms to form the corresponding monoalkylphosphoryl dichloride and then further reacting this product with anaqueous sodium phenate solution. The alcohol is preferably slowly addedto the POCl with suitable agitation and at a rate to maintain thereaction temperature at from about 10 to 20 C. Agitation iscontinued fora period of from about 1 to 2 hours and the temperature is then allowedto rise to about 20 to 30 C., after which the reaction mixture is againagitated for a period of from about 1 to 2 hours. Hydrogen chloride gasis evolved as a result of the reaction of the POC1 and the alcohol maybe continuously removed. The resulting monoalkyl phosphoryl dichlorideis then added to an aqueous sodium phenate solution at a temperature ofabout to 5 C. at a rate to maintain that temperature. The concentrationof the sodium phenate solution may range from about 25 to about 40% orhigher. After the alkyl phosphoryl dichloride has been added, themixture may be agitated for about an hour and then allowed to reach roomtemperature while being stirred. Upon standing an ester layer and anaqueous layer will Typical value Property:

Acidity percent 0003 Color (APHA 50 Moisture percent (Karl Fischermethod) 0.10 Refractive index at 25 C 1.509 Specific gravity 25/25 C1.091

1 American Public Health Association.

The halohydrocarbon employed in the fuels of the invention may be analkyl halide such as chlorobromomethane, tetrabromoacetylene,trichloroethylene, ethylene dichloride or ethylene dibromide; analicyclic halogenated compound such as chlorocyclopentane ortrichlorocyclopentane; an aromatic halogen compound such aschlorobenzene, dibromobenzene, trichlorobenzene, dibromotoluene orbromoxylene; or a mixture of such halohydrocarbons. The foregoinghalohydrocarbons are not all equally effective for the present purpose.Ethylene dichloride, ethylene dibromide and certain mixtures thereof areparticularly preferred because of their effectiveness, which may bepartly due to their volatility and chemical stability being appropriatefor them to accompany the lead compounds into the reactions which occurduring combustion in an engine.

The amounts of the monoalkyl diphenyl phosphate and the halohydrocarbonemployed in accordance with the invention are dependent upon thequantity of tetraethyl lead or equivalent lead compound employed in thegasoline. For this reason, these amounts can be best expressed in termsof theories, one theory being the amount of a constituentstoichiometrically equivalent to the lead in the gasoline. For example,it is the ratio Cl /Pb for chlorine or Pz/Pbg for phosphorus. Thismethod of expressing additive concentrations is a con ventional one andwill be familiar to those skilled in the fuels art. The total theoriesof phosphorus, chlorine and bromine may be as low as 1.65 but arepreferably at least 1.75 when the gasoline contains more than 2.5 cc. oftetra ethyl lead per gallon and should not exceed 4.00. The monoalkyldiphenyl phosphate may be added to the I fuels of the invention inamounts rangingfrom about 0.05

theory to about 1.0 theory, concentrations of about 0.1 to 0.8 theorybeing preferred and concentrations of about 0.15 to 0. 4 theory beingparticularly advantageous.

The halohydrocarbon scavenger may be present in the fuels of theinvention in amounts ranging from 1.6 theories to about 3.0 theories,concentrations of from 1.7 theories to 2.1 theories being preferred.Conventional lead fluids contain some halohydrocarbon scavenger inaddition to the alkyl lead compound. Therefore, if a conventional leadfluid is used, the amount of halohydrocarbon must be adjusted by furtheraddition of ethylene dichloride or dibromide in order to bring the totalhalohydrocarbon content up to from 1.6 to 3.0 theories. Usually suchfluids contain 1.0 theor of ethylene dichloride and 0.5 theory ofethylene dibromide and it is therefore necessary to add from :1 to 1:5theories of additional halohydrocarbon for the purpose of the presentinvention. Furthermore, the theories of halohydrocarbon in total must besuch as to give a ratio of at least 3 to 1 to the mono alkyl diphenylphosphate but not more than 32 to 1. of the present invention, thetheory ratio of ethylene .dichloride to ethylene dibromide is between2.4 and 4.2 to 1.

The tetraethyl lead content of the gasolines in which the additiveagents of the invention are incorporated may range from about 2.0 to 4.6cc. per gallon. In addition, the gasolines may contain solvent oilsconsisting of hydrocarbon mixtures having a Saybolt viscosity at 100 P.not above 450 seconds, a 50% distillation point above about 350 F. atmm. Hg and an A.P.I. gravity between about 18 and 28; corrosioninhibitors such as Santolene C, which is a phorphous-containing dimer oflinoleic acid, amines and amine phosphates and nitrates; gum inhibitorssuch as N,Ndi-secondary butyl p-phenylenediamine,2,4-dimethyl-6-tertiary butylphenol and 2,6- ditertiarybutyl-4-methylphenol; anti-icing agents such as isopropanol, hexyleneglycol. Carbitol and dimethyl formamide; dyes such as 1,4-diisopropylamino anthraquinone and pdimethyl aminazobenzene; dye stabilizers suchas ethylene diamine; and similar additive materials commonly used ingasolines.

Gasoline as used in connection with the present invention is awell-known article of commerce for use in internal combustion enginesoperating on the Otto cycle. It is supplied in different gradesdepending upon the type of service. 'The grade of gasoline to which theinvention particularly applies is motor gasoline, which the AmericanSociety for Testing Materials broadly characterizes as a complex mixturecomposed almost entirely of relatively volatile hydrocarbons which varywidely in their physical and chemical properties." Motor gasoline foruse in accordance with the present invention meets ASTM specificationD-439-56T, in types A, B, and C. It is composed of a mixture of varioustypes of hydrocarbons, including aromatics, olefins, parafiins',isoparaflins, naphthenes and sometimes some diolefins. These mixturesare obtained from petroleum by refining processes including fractionaldistillation,'catalytic cracking, hydroforming, alkylation andextraction.

Motor gasoline boils between about 80 F. initial boiling point and about450 F. when tested by ASTM method D 86. Its vapor pressure by ASTMmethod D 323 varies for use at different seasons between 7 and lbs. persquare inch at 100 F. An important propcity of motor gasoline is itsoctane member as measured by ASTM method D 908. The present invention isparticularly applicable to gasoline having at least 83 octane number bythis method and containing at least 2 cc. of tetraethyl lead per gallon.The composition of gasoline according to the present invention comprisesat least 95% by weight of hydrocarbons. The invention is particularlyeifective in motor gasoline containing at least 30% aromatics and up to60% aromatics.

A particularly preferred method of incorporating the additive materialsof the invention into gasolines is to include them in an additiveconcentrate containing tetraethyl lead or a similar alkyl lead compound.Such a concentrate may contain, in critical proportions to each other,from 0.05 to 2.0 theories of the monoalkyl diphenyl phosphate and from1.6 to 3.0 theories of the halohydrocarbon, based on the lead content,and may include other gasoline additive materials such as those setforth above. A typical concentrate containing tetra- In a particularlypreferred embodiment ethyl lead and the additive materials of theinvention may have the following composition by weight:

Tetraethyl lead 53.5%. C -oxo diphenyl phosphate 6.4% or 0.2 theory.Ethylene dibromide 15.5% or 0.5 theory. Ethylene dichloride 19.6% or 1.2theories. Gum inhibitor, rust inhibitor,

dyes, dye stabilizers, etc 5.0%.

The invention may be further illustrated by referring to the followingexamples.

EXAMPLE I In order to demonstrate the effectiveness of the improvedfuels of the invention upon octane requirement increase, surfaceignition and spark plug fouling in modern automotive engines, a seriesof tests was conducted in which five different makes of 1957 automobileshaving compression ratios above 9.0 to 1 were operated upon a premiumquality gasoline containing 3 cc. of tetraethyl lead per gallon and 1.5theories of a scavenger agent consisting of 0.5 theory of ethylenedibromide and 1.0 theory of ethylene dichloride. Typical inspections ofthe gasoline used in these tests were as follows:

A.S.T.M. Distillation D-86:

Initial :boiling point, F 104 10% boiling point, F 136 50% boilingpoint, F 216 90% boiling point, F 291 Final boiling point, F 345Residue, percent 0.8 Loss, percent 1.2 Reid vapor pressure 7.6 A.P.I.gravity 56.4 General Motors gum 2.20 Research octane number 101.4 Motoroctane number 89.2

The same automobiles were then operated on a similar gasoline to whichhad been added 0.2 theory of C -oxo diphenyl phosphate and 0.2 theory ofethylene dichloride, giving a total halohydrocarbon content of 1.7theories. The equilibrium octane requirements of the engines weredetermined for both gasolines from the standpoint of spark knock andsurface ignition of the wild knock (rolls) and wild ping" (snap) types,using commercial reference fuels as a basis for comparison. Rumble, arapid surface ignition which causes vibrational noises at speeds of from40 to 70 miles per hour and is independent of fuel octane number, wasmeasured and spark plug fouling as indicated by the percent of misfircsat 15 to 70 miles per hour registered by an electronic counter wasdetermined.

it is to be noted that the requirements in octane number, that is thelevels of octane number at which both spark knock and surface ignitionno longer occurred, were determined at equilibrium. It is important thatequilibrium conditions be reached in measurements of this sort becauseinitially the addition of an intended beneficiating agent to gasolinemay show some improvement in suppressing surface ignition in an enginebut upon continued use this agent may promote spark knock, with theultimate result that a gasoline of higher octane number is required togive no-noise operation of the engine than was required before the agentwas added to the gasoline. The attainment of equilibrium for these testsis achieved only after the test automobiles have been run for at least3000 miles. The results of these tests are shown in the following table.V

Table I Car. I9.5:1C.R. Car II-10:lC.R. Car III0.5:1C.R. CarIV-9.7:i.C.R. Car V0.25:1C.R.

FuclA Fuel B 1 FuelA 1 Fuel B 9 Fuel A 1 Fuel B 2 Fuel A Fuel 13 2 FuelA 1 Fuel B 2 Spark knock equilibrium octane require- 011 04. 95% 94 9295 93% 94 93 93% 90/; Surface ignition 4 equilibrium quirement Q6 6 None97% 92% 97 A 93 94% 5 None 90 89 Rumble 3 105 6 None 8 105 5 None 3 1055 None 5 None 6 None 6 None 1w one Spark plug foulin percent rnisfires.40 0 10 0 33 14 0 0 i9 3 No-noise octane advantage for fuel B V. 5 4 1%3 l Fuel A contained 3 cc. tetraethyl lead per gallon and 1.5 theoriesof halohydrocarbon scavenger for lead, including 1 theory of ethylenedichloride and 0.5 theory of ethylene dibromide.

m ilguel B was identical to Fuel A except that it also contained 0.2theory of C's-0x0 diphenyl phosphate and 0.2 theory of additionalethylene die or e.

3 Rumble is not strictly proportional to fuel octane quality but it canbe eliminated by increasing octane number. Numbers give maximum octanefuel with which rumble is heard. It is a vibration which occurs in carswith high compression ratios.

4 Wild knock (rolls) and Wild ping (snap) types of surface ignition. 4

5 This notation means that the indicated phenomenon of surface ignitionor rumble was Wholly absent and that therefore no measurement of octanenumber was needed. When either oithcse phenomenawas present altera carhad been run to equilibrium with the test fuel, then an octane requrement was determined in terms of the minimum octane number ofreferenccfuel required by the car on the road to give no noise of spark knock orsurface ignition The data in the foregoing table show that the octaneTable II requirement at equilibrium for eliminating the noise ofEquilibrium octane spark knock, surface ignition and rumble and the1ncifor ondence of spark plug misfiring were both markedly lower CarGasoline when the fuels of thcinvention were used and that the igllllljliicg i. 10 presence of the special combination of C -oxodiphenyl phosphate, ethylene dichloride and ethylene dibrornide in Basefuel 99 100 I Base fuel heories trieresyl 100% 00 accordance with thepresent invention gave an advantage Bphofspliate, 99 9g use no 2 of from1 to 5 octane numbers in the no-noisc equilibrium 1r Baske fuell 0.4theories tricresyl 09% 100% D 0513 ate. level. Intact, in every testexcept that for equilibrium Basefuel as 100 III Base fuel 0.4 theoriestricresyl 90% 98 requirement to overcome spark-knock in car I, the re-40 Bphofspliate y 99V use ue 1 00 quirement was consistently lower afterrunning on fuel v {Basefue1+ 0.4 theories tricrcsyl 90% 97 2 phosphate.B than after running on fuel A. Base fuel 1 a7 90% V Base fuel 0.4theories trieresyl 98% None phosphate.

EXAMPLE II 1 Base fuel contained 2.9 cc. of tetraet'nyl lead, 1.0 theoryof ethylene dichloride and 0.5 theory of ethylene dibromidc and hadarcsearch octane A second series of tests similar to those described innumber about the preceding example was carried out comparing a gaso-EXAMPLE In line similar to that of the preceding example but containn rr to rmine what effect the monoalkyl diing 2.9 cc. of tctraethyl leadper gallon and 1.5 theories of Phenyl Phosphates halohydrocarbonsemployed in f th 1 cordance with the invention would have on the octaneScavenger conslstmg of a mmture e y em 1 number of a gasoline to whichthey were added, direct and etIll/lens dichloride With another batch ofthe same match octane number determinations were made using gasoline towhich had been added 0.4 theory of tricresyl premium grade commercialleaded gasolines, without and phosphate, a compound used heretofore incommercial with the addition of theory of CB'OXO p y P asolines in orderto prevent spark plug fouling and asga f of additional y edichloridesociated difficulties caused by lead deposit formation. The edata Obtained m these tests are Shown m Table cars were driven undercity-suburban driving conditions Table for a total of about 12,000miles. Tests were carried out Research Octane number Motor Octane numberusing standard commercial reference fuels and the stand- I on 3rdUniontown procedure to dctcimine equilibrium oc- B I f 1 i in gqg f 1 fi i gg g f use no ue num or no no number tane requirements from thestandpoint of spark knock additive, dugpo additive 4 an? to and surfaceignition. It was found that although the triammo crcsyl phosphate had abeneficial effect with respect to 10L 4 0 8M 8M 0 surface ignition inall but one of the cars, the benefit -8- 33% gg-g g was offset by anincrease in the spark-knock requirement 8 3%? 8 of from /2 to 3%numbers. The fuels of the present ini8}; 8 22.8 8 vcntion as shown inTable I are thus superior to fuels 185- g 33g 33.8 8 containing suchcommercial additives of the prior art as The additive consisted of 0.2theory of C -oxo dc hen l hos hate Shown y the data m Table II belowand0.2 theory of ethylene dichloride. p y p p From the above it can be seenthat the incorporation of the monoalkyl diphenyl phosphate andhalohydrocarb'on in gasolines in proportions in accordance with thepresent invention does not significantly aflect the octane quality ofthe fuel itself.

EXAMPLE IV For comparative purposes, additional direct match octanedeterminations were carried out using commercial leaded gasolinessimilar to that employed in the preceding example without and with theaddition of various phosphorus compounds. The results of these tests aresummarized in the following table.

0.2 theory of C -oxo diphenyl phosphate, 1.2 theories of ethylenedichloride and 0.5 theory of ethylene dibromide was stable attemperatures down to 45 C., well below the temperatures normallyencountered, while the additive agents separated out of samplescontaining tricresyl phosphate, tolyl dimethyl phosphate, andtri-(chloroisopropyl)thiono-phosphate, commercial additives, attemperatures considerably warmer than 45 C. In addition, the solidmaterial which separated out of the sample containing tricresylphosphate did not readily redissolve when the sample was warmed to roomtemperature.

Table IV Research Octane Number Motor Octane Number 00110911- I Additivetration, Change in 7 Change in Theories Base Fuel Octane Base FuelOctane Base Fuel Addi- Number Base Fuel Addl- Number tive due to tlvedue to Additive Additive 0. 2 100. 5 109. 5 89. 8 89. 2 -0. e TriethylPhosphate 0. 4 100. 5 100.4 -0.1 89.8 87. 8 2. 0 1. 0 100. 5 99. 5 -1.089. 8 86. 4 3. 4 0. 2 100.7 100. 7 0 89. 5 88.5 -1.0 TriisooctylPhosphate 0.4 100.7 100. 1 0. 6 89. 5 88.2 1. 3 1. 0 100. 7 99.8 0. 989.5 87.4 2. 1 0.2 88.8 88.2 06 Triisopropyl Phosphite 0.4 88. 8 87.5 1.3 1. 0 88. 8 85.5 -a. a 0. 2 88. 7 88.3 0. 4 Triehloropropyl Phosphite0.4 88. 7 87. 6 1. 1 1. 0 88.7 85. 8 -2. 9 0. 2 10 89. 9 89. 7 0. 2Triphenyl Phosphite 0. 4 101. 3 100.8 0. 5 90.0 90.0 0

1. 0 101. 3 100.7 0. 6 90.1 89.0 1. 1 v i 0.2 101.3 101.3 0 90.1 89.7-0.4 Triphenyl Phosphate 0.4 101.3 101. 3 0 89. 9 89. 9 0

' 1. 0 101.1 100.5 0. 0 89.2 89.7 0. 5 0. 2 101. 9 100.8 -0. 5 88.7 88.3-0. 4 Trlcresyl Phosphlte 0.4 101. 6 101. 3 0. 8 88.6 88.6 0

. 1. 0 101. 3 101.1 0. 2 88.8 88.1 0. 7 0. 2 101.1 100.9 0. 2 89. 2 88.7-0. 5 Butyl Diphenyl Phosphate 0. 4 101. 1 100. 8 0. 3 89.2 88.6 0. 6 1.0 100.9 100. a 0. 6 88.9 87.8 -1. 1 Tributyl Phosphate" 1. 0 87.1 85.9 1. 2 84.1 81. 4 2, 7 Tributyl Phosphite.. 1. 0 86. 7- 85.1 1. 6 84. 781.1 3. 6 0. 2 100.7 100. 5 0. 2 90. 3 89.3 1. 0 TriehloroisopropylThionophosphate 0.4 100.7 100.0 0. 7 90. 3 88.6 -1 7 1. 0 100.7 99. 3-1. 4 90. 3 86. 9 3. 4

0. 2 100. 9 100.9 0 89. 7 89. 7 0 Dlmethyl Xylyl Phosphate 0. 4 100.9100.7 0. 2 89.8 89.1 0. 7 i. 0 100.9 100. 5 -0. 4 89.7 88.6 -1. 1 0. 299. 4 99. 4 0 V 89.0 87.8 -1. 2 Hexamethyl Phosphoramide 0. 4 99.7 99. 40. 3 89.0 87. 3 1. 7 1.0 99.7 98.8 -0.9 89.2 85.5 -s.7 0.2 100.4 100.30.1 89.2 88.6 --0.6 Diethyl Ethyl Phosphonate 0.4 100.4 100.1 0.2 89.287.8 -1.4 1. 0 100.4 99. 7 0. 7 89.2 86. 8 -2. 4 Diethyl EthylPhosphonate Equal 0.2 101.6 101.1 0.5 88.9 88.6 0.3 EthyleneDichloride 1. 0 101.7 100.8 0. 9 90.1 86.7 3. 4 Isooctyl DiphenylPhosphate Equal 0.2 101.5 101.5 0 89.4 89.4 0 Ethylene Dichloride 0. 4101. 5 101. a 0 89.4 89. 4 0 1. 0 101.8. 101. a 0. 3 89. 4 89.4 0

The above data show the effect of a large number of EXAMPLE V1representative phosphorus compounds upon the octane quality of leadedgasolines to which they were added. It of g y phosphatehtolyl dlmethylwill be noted that of the compounds listed, only the last p 05p ate andomlsopwyyl)'thlono'phosphfm one in Table Iv namely the additive of thePresent were contacted with distilled water in order to determine a ivention, did not suppress octane quality. Several of the gig ggi g i i ifl g g samples 5 compounds, including compounds now usedcommercialallowed t n f en th 3 Y g ly as gasoline additives andincluding butyl diphenyl phosof th 0 i or g f a o W 1;. 5 phate, whichis a monoalkyl diphenyl phosphate outside th 833 r' f i the scope of thepresent invention, caused a loss in motor re 1 a Welg e erm e t was mmat t e octane number up to as high as 3.7 octane numbers when dlphenylPhosphate a less than half as Soluble added to the gasoline in 1 theoryamounts as the tri-(chloroisopropyl)throno-phosphate and about Yone-one-hundredth as soluble as the tolyl dimethyl phos- EXAMPLE Vphate. The Cg-OXO diphenyl phosphate used in the fuels Tests were alsoconducted to determine the suitability of the invention is thus lesssusceptible to being washed of the fuels of the present invention foruses where they out of the fuel by water present in storage tanks andthe p are subjected to extremely low temperatures. Various adlike thanare the other two C mP both used @0111- ditive agents were'incorporatedin samples of a cornmerme clally as gasoline additives.

cial leaded gasoline at a concentration of 0.2 theory and the gasolinewas then refrigerated to determine the tem- EXAMPLE VII perature atwhichthe agents were precipitated from the In order to test the stability andcompatibility of the fuel. It was found that the leaded gasolinecontaining additives used in the fuels of the invention with otheradditives, an additive concentrate consisting of 37.9 parts of solventoil, 1.5 parts of C -oxo diphenyl phosphate, 0.6 part of ethylenedichloride and 1.14 parts of 2-methyl- 2,4-pentanediol was prepared.This mixture was added to a leaded gasoline in proportion to give a fuelcontaining 0.5% solvent oil, 0.2 theory of C -oxo diphenyl phosphate,0.2 theory of extra ethylene dichloride and 0.15% of 2-methyl-2,4-pentanediol. With this additive, the fuel had a reducedtendency to cause intake valve deposits, spark plug fouling, octanerequirement increase and carburetor icing. The concentrate preparedremained homogeneous when stored for one month at -25 C. and when storedin sunlight at room temperature for one month.

EXAMPLE VIII Two samples, No. 1 and No. 2, of commercial premium motorgasolines of spring grade volatility were tested for potential gum byASTM method 'D873, without and with the addition of phosphate additives.These gasolines contained 3 cc. of tetra ethyl lead per gallon. Theyalso contained, as is customary in commercial motor gasoline, the usualhalide scavenger consisting of 1.0 theory of ethylene dichloride and 0.5theory of ethylene dibromide.

To each gasoline, the following agents were added:

(A) 0.2 theory of C -oxo diphenyl phosphate and 0.2

theory of ethylene dichloride. (B) 0.2 theory of tricresyl Phosphate.

The samples containing (A) were compositions in accordance with thepresent invention, containing in total a mixture of 0.2. theory of C-oxo diphenyl phosphate, 1.2 theory of ethylene dichloride and 0.5theory of ethylene These results clearly show the superiority of thecomposition of the present invention in the lower value of potentialgum, thus confirming its high degree of stability.

The additive compositions employed in the fuels of the present inventionhave also shown some effect like that of solvent oil in gasolines. Two1957 high compression automobiles operated upon the fuels of theinvention were found to have a lower level of intake valve undersidedeposits and intake system deposits than did the same cars when operatedon a similar fuel not containing the mixture of C -oxo diphenylphosphate, ethylene dichloride and ethylene dibromide of the presentinvention.

As can be seen from the preceding examples, the additive agents of thisinvention meet all of the criteria for an additive intended to overcomethe detrimental efiects of tetraethyl lead and similar anti-knock agentsin gasolines and are surprisingly superior to phosphorus-containingmaterials which have been employed heretofore. The additives of theinvention-- (1) Decrease surface ignition due to lead deposits (2)Decrease rumble (3) Decrease spark plug fouling (4) Do not raise sparkknock equilibrium requirement (5) Do not depress fuel octane quality (6)Are not extracted by water, and

(7) Possess excellent storage stability properties over a widetemperature range.

This surprising overall superiority makes the additives of thisinvention considerably more attractive for use in lead-containinggasolines than other materials proposed heretofore, all of which fail tomeet one or more of the above-listed criteria.

It is apparent that, while the present invention is of application toany leaded gasoline including automotive type gasolines, marine typegasolines and aviation gasolines, it is of particular application tomotor gasolines intended for use in modern high-compression engineswhich are especially susceptible to the adverse efiects arising from theformation of lead deposits therein.

What is claimed is:

1. An improved gasoline additive composition the major proportion ofwhich comprises a volatile tetraalkyl lead compound as an anti-knockagent and a mixture of 1 part of a C monoalkyl diphenyl phosphate andfrom 3 to 32 parts of a halogenated hydrocarbon boiling below 250 C., asa scavenger agent, said mixture being present in a concentration between1.75 and 4.00 theories based on the lead and said halogenatedhydrocarbon scavenger agent containing from 0.1 to 1.5 theories of astoichiometric excess of a chlorinated hydrocarbon scavenger.

2. An improved gasoline additive composition the major proportion ofwhich comprises tetraethyl lead, from about 1.7 to about 2.1 theories ofa halogenated hydro carbon boiling between 50 C. and 250 C. containingfrom 0.1 to 1.5 theories of a stoichiometric excess of ethylenedichloride, and from about 0.15 to about 0.4 theory of a C monoalkyldiphenyl phosphate, said halogenated hydrocarbon being present in aratio between 3 and 32 to 1 to said monoalkyl diphenyl phosphate.

3. An additive composition as defined by claim 2 wherein said monoalkyldiphenyl phosphate is Cg-OXO diphenyl phosphate.

4. An additive composition as defined by claim 2 wherein saidhalogenated hydrocarbon is a mixture of ethylene dichloride and ethylenedibromide.

5. An improved gasoline anti-knock additive the major proportion ofwhich comprises tetraethyl lead, from about 1.7 to 2.1 theories of amixture of ethylene dichloride and ethylene dibrornide in theory ratiobetween 2.4 and 4.2 of said dichloride to 1 of said dibromide andcontaining about 0.2 theory of a stoichiometric excess of ethylenedichloride and from 0.15 to 0.4 theory of C3-OXO diphenyl phosphate.

6. A gasoline containing from about 2.0 to about 4.6 cc. of tetraalkyllead compound per gallon, about 1.7 to 2.1 theories of a halogenatedhydrocarbon boiling below 250 C. containing from 0.1 to 1.5 theories ofa stoichiometric excess of ethylene dichloride; and about 0.15 to 0.4theory of a C monoalkyl diphenyl phosphate.

.7. A gasoline as defined by claim 6 wherein said monoalkyl diphenylphosphate is isooctyl diphenyl phosphate.

8. A gasoline as defined by claim 6 wherein said monoalkyl diphenylphosphate is C -oxo diphenyl phosphate.

9. An improved gasoline composition comprising at least 95% ofhydrocarbons boiling between F. and 450 F., from 2.0 to 4.6 cc. oftetraethyl lead per gallon, from about 1.7 to about 2.1 theories of amixture of ethylene dichloride and ethylene dibromide and containingabout 0.2 theory of a stoichiometric excess of ethylene dichloride, andfrom about 0.15 to about 0.4 theory of C -oxo diphenyl phosphate.

(References on following page) References Cited in the file of thispatent UNITED STATES PATENTS Knutson et a1. Feb. 1, 1944 Fry et a1. May8, 1945 Campbell Aug. 13, 1946 Yust et a1 Oct. 2, 1956 Lusebrink et a1.Oct. 2, 1956 Andress Oct. 21, 1958 Yust et a1 June 2, 1959 Pellegrini eta1 July 28, 1959 14 Orlofl et a1 Nov. 3, 1959 Heron Sept. 12, 1961FOREIGN PATENTS Canada July 18, 1944 Great Britain Nov. 26, 1952 FranceNov. 5, 1953 France Nov. 26, 1954 OTHER REFERENCES Ind. and Eng. Chem,vol. 43, No. 3, March 1951, Antiknock Antagonists, by Livingston, pp.663- 670.

1. AN IMPROVED GASOLINE ADDITIVE COMPOSITION THE MAJOR PROPORTION OFWHICH COMPRISES A VOLATILE TETRAALKYL LEAD COMPOUND AS AN ANTI-KNOCKAGENT AND A MIXTURE OF 1 PART OF A C8 MONOALKYL DIPHENYL PHOSPHATE ANDFROM 3 TO 32 PARTS OF A HALOGENATED HYDROCARBON BOILING BELOW 250* C. ASA SCAVENGER AGENT, SAID MIXTURE BEING PRESENT IN A CONCENTRATION BETWEEN1.75 AND 4.00 THEORIES BASED ON THE LEAD AND SAID HALOGENATEDHYDROCARBON SCAVENGER AGENT CONTAINING FROM 0.1 TO 1.5 THEORIES OF ASTOICHIOMETRIC EXCESS OF A CHLORINATED HYDROCARBON SCAVENGER.